In recent years, liquid crystal displays having touch panel have been developed rapidly. According to their structures, the liquid crystal displays having touch panel are mainly classified into Touch-Panel-Add-On type, Touch-Panel-On-Cell type, and Touch-Panel-In-Cell type.
FIG. 1 illustrates a touch sensor of a Touch-Panel-Add-On type liquid crystal display in the conventional art. As shown in FIG. 1, the touch sensor comprises: a substrate 1, a metal bridge 2, a first insulation layer 3, a touch sensing layer 4 in an X direction, a touch sensing layer 4′ in a Y direction, and a second insulation layer 5. The touch sensing layer 4 in the X direction is discontinuous and becomes electrically communicated by the metal bridge 2. In addition, a cover glass (not shown) may be disposed on a surface of the touch sensor, so as to protect the surface of the touch sensor and block a circumference light leakage region. In general cases, the substrate 1 is also formed of glass, thus the touch sensor having two layers of glass is called as Glass to Glass Touch Sensor.
A manufacturing method of the above touch sensor comprises the following steps:
Step 101, depositing a metal layer on the substrate 1, and performing a first patterning process on the metal layer by using a mask plate to obtain the metal bridge 2. In addition, a metal layer (not shown) in a bonding region is also obtained. The bonding region refers to the region which is connected with a flexible circuit plate (FPC).
Step 102, depositing the first insulation layer 3 on the substrate 1 after the step 101, and performing a second patterning process on the first insulation layer 3 by using a mask plate to form contact holes in the first insulation layer 3, wherein these contact holes expose corresponding portions of the metal bridges 2. In addition, in this patterning process, the first insulation layer 3 in the bonding region is etched away to expose the metal layer in the bonding region.
Step 103, depositing a transparent conductive layer on the substrate 1 after the step 102, and performing a third patterning process on the transparent conductive layer by using a mask plate to obtain the touch sensing layer 4 in the X direction and the touch sensing layer 4′ in the Y direction. In addition, a transparent conductive layer in the bonding region which covers the metal layer is also obtained. The metal layer and the conductive layer contacting with each other in the bonding region are connected with the FPC, so as to turn on the touch sensor and the thin film transistor liquid crystal display (TFT-LCD) panel in the liquid crystal display having touch panel. For example, the transparent conductive layer is formed of indium tin oxide (ITO).
It can be seen from FIG. 1 that the touch sensing layer 4 in the X direction is discontinuous and becomes electrically communicated by the metal bridge 2 and the touch sensing layer 4′ in the Y direction is continuous itself.
Here, the X direction refers to the direction parallel to the paper surface, and the Y direction refers to the direction perpendicular to the paper surface. The X direction and the Y direction are perpendicular to each other. The touch sensing layer 4 in the X direction and the touch sensing layer 4′ in the Y direction do not connect with each other.
Step 104, depositing the second insulation layer 5 on the substrate 1 after the step 103, and performing a fourth patterning process on the second insulation layer 5 by using a mask plate to obtain the second insulation layer 5 protecting the touch sensing layers in the X and Y directions. So far, the manufacturing of the touch sensor is completed.
It can be seen from the above procedure that it needs to perform patterning process four times by using four mask plates to manufacture the touch sensor in the conventional art, thus the number of the manufacturing steps is relatively large, and the manufacturing cost is relatively high.